/Engine/Plugins/Online/OnlineSubsystem/Source/Public/Interfaces/OnlinePurchaseInterface.h
Delegate called when we are informed of a new receipt we did not initiate in-game
typedef TMulticastDelegate_OneParam< void, const [FUniqueNetId](API\Runtime\CoreOnline\Online\FUniqueNetId) & > FOnUnexpectedPurchaseReceipt